APPENDIX TO DECADE V. 



5 



liiglily ornamented, but never two alike. Tlie sutural pores 

 appear more numerous in the sculptured specimens, there being 

 5 to each ocular plate. 



Localifi/.—TuOWiLU (or Grf.y) Cpialk of Dover. 



2. ,S'. Clarkii, Forbes, MS. 



Body 6 lines in diameter, 4 in height ; apical disk rather small, 

 scarcely exceeding 3 lines in diameter, the plates rough, with raised points ; 

 each genital plate Avith five furrows leading to the sutural pores, which 

 are like those of S. petalifera, but larger ; ambulacra rather narrower 

 than in *S'. petalifera ; spines slender, cylindrical, finely striated and 

 granulated, the longest exceeding 1| inches in length, and less than 1 line 

 in diameter, frequently forked at their extremities, and sometimes bent 

 and distorted. 



This species is scarcely to be distinguished from those Warminster 

 specimens Avhich have been referred to S. gibba^ Ag. ; but is 

 entirely distinct from the mould of M. Agassiz's original example. 



Locality. — Giif.y Chalk, Dover. (Mus. Pract. Geol. and Brit. Mus.) 



3. S. granulosa, Forbes, MS. Morris's Cat., 2nd ed. p. 89. S. scuti- 

 gera 7 Forbes, in Dixon's Geol. Sussex, t. 25, f. 24. 



Body small, lat. 6, alt. 3-|- mill., — sometimes it measures only li lines in 

 diameter ; oral opening large, not depressed ; apical disk very large, 

 lat. lines, plates finely sculptured with rugose lines, sometimes radiated, 

 sutures quite simple ; primary tubercles fev^r and prominent ; miliary zone 

 irregular, granulose ; ambulacra narrow. 



Locality. — Lower Chalk, Dover. Found along with Cyphosoma 

 simplex and numerous Bryozoa, in the hard gritty beds of White 

 Chalk. (Mus. Pract. Geol., Brit. Mus.) 



4. S. Portlockii, Forbes, MS. Morris's Cat., 2nd ed., p. 89. Cidaris 

 vesiculosus, Portl., Geol. Rep., t. 18, f. 5. S. scutigera 2 Forbes, Dixon's 

 Sussex, pi. 25, f. 23. 8. geometrica, Ag., Mon. d'Ech. Salenies, p. 11, 

 t. 1, f. 25-32. 



Body subglobose, elevated, convex above, contracted and concave 

 beneath, lat. 9, alt. 8 lines ; mouth small, lat. 3 lines ; apical disk 

 moderate, lat. 6 lines ; plates slightly radiate ; sutural perforations rather 

 indented ; ambulacra narrow, sinuous, tubercles separated by two rows of 

 granules ; interambulacral tubercles 7-8, those near the mouth (3, 4) very 

 small ; miliary zone wide. 



The specimen described belongs to Mr. Searles Wood ; another, in 

 the cabinet of Mr. John King, of Norwich, measures 11 lines in 

 height, and the same in diameter ; and there is a fine specimen in 

 the Hunterian Collection. The agreement of this species with 

 S. geometrica has been overlooked on account of an error in 



